Joining state detection film, joining state detection device, and joining state detection method

Abstract

An object is to provide a joining state detection film, a joining state detection device, and a joining state detection method, capable of detecting a joining state of a joining portion of two members from the outside. [Solution]A film containing a mechanoluminescent substance is formed on a surface, on a side opposite to a joining surface, of at least one member of two members that are joined at joining parts each having the joining surface, and physical stimulation is applied thereto.

The invention claimed is: 
     
       1. A joining state detection method for detecting a joining state of two members that are joined at joining parts each having a joining surface, the method comprising the steps of:
 forming the joining state detection film containing a mechanoluminescent substance on a first surface of a first of the two joining parts, the first surface being opposite to the joining surface of the first joining part; and 
 physically stimulating the joining part such that light is emitted from a luminescent part of the joining state detection film and light is not emitted from a non-luminescent part of the joining state detection film and an area of the non-luminescent part indicates an area of the joining surface where the two members are not joined. 
 
     
     
       2. The joining state detection method according to  claim 1 , wherein the mechanoluminescent substance contained in the joining state detection film is a substance represented by SrAl 2 O 4  that is doped with Eu 2+ , a substance represented by SrAl 2 O 4  that is doped with at least one of Eu 2+ , Ho 3+ , Dy 2+ , M 1 , M 2 , and M 3  (M 1 , M 2 , and M 3  are monovalent to trivalent different metal ions), or a substance represented by CaYAl 3 O 7  that is doped with Eu 2+ . 
     
     
       3. The joining state detection method according to  claim 1 , wherein the two members are joined using an adhesive, a rivet, a bolt and a nut, a screw, a clinching fastener, and swaging. 
     
     
       4. The joining state detection method according to  claim 1 , wherein the two members are joined by static electricity, anodic bonding, or welding. 
     
     
       5. The joining state detection method according to  claim 1 , wherein a joining strength between the two members is detected on a basis of an area ratio of the luminescent part to the joining surface. 
     
     
       6. The joining state detection method according to  claim 1 , wherein the step of forming a joining state detection film further forms a joining state visualization film containing a mechanoluminescent substance on at least one of a side surface and an end surface of the joining part.